What is Strontium

Strontium (pronunciation: STRON-she-em) is a soft, silvery element that belongs to the family of alkali earth metals and is represented by the chemical symbol Sr ^{[1, 2]}. Being chemically highly reactive, it reacts with water and burns in the air ^{[1, 3]}.

Isotopes

Strontium is characterized by four naturally occurring isotopes, including ⁸⁴Sr, ⁸⁶Sr, ⁸⁷Sr, and ⁸⁸Sr, all of which are stable ^[4]. In addition to these four isotopes, more than 30 unstable isotopes exist, out of which the longest-lived are ⁸⁵Sr and ⁹⁰Sr with half-lives of 64.853 days and 28.9 years respectively ^[5].

Where is Strontium Found

Strontium is mainly obtained from the mineral ores strontianite (SrCO₃) and celestite (SrSO₄) ^{[1, 6]}. It is commercially produced through reduction of strontium oxide (SrO) with aluminum, or through electrolysis of the molten mixture of potassium chloride and strontium chloride ^[1]. Today, the leading producers of strontium are China, Spain, and Mexico while the top reserve holding country is China ^[1].

History

Origin of its Name: It is named after the small Scottish town Strontian ^[1].

Who discovered it: The element was first found by the Northern Irish physicist and chemist Adair Crawford ^[1].

When and How was it Discovered

In 1787, Adair Crawford analyzed an unusual rock that he found in a mine at Strontian ^[1]. He named the new mineral, which consisted of an unknown element, strontia ^[1]. A Scottish chemist, Thomas Charles Hope, investigated the element in 1791 and found that it causes the candle flame to burn red ^[1]. At the same time, Martin Heinrich Klaproth independently worked with the mineral in Germany and successfully produced both oxide and hydroxide of strontium ^[1].

In 1808, Sir Humphry Davy isolated strontium metal through electrolysis of a molten salt of strontium sulfate ^[6]. He used mercury and platinum as negative and positive electrodes respectively ^[6].

Strontium Identification
Atomic number	38 [1]
CAS number	7440-24-6 [1]
Position in the periodic table	Group	Period	Block
	2 [1]	5 [1]	s [1]

Properties and Characteristics of Strontium

Atomic Data of Strontium (Element 38)

What is it Used for

• Strontium salts are known to produce brilliant red color and are commonly added to firework mixtures and road flares ^{[1, 3]}.
• It is used in ferrite magnets production and zinc refining processes ^[3].
• Strontium aluminate and strontium carbonate are used in ‘glow-in-the-dark’ plastics and paints in which the light absorbed during the day are slowly released afterward ^[1].
• The radioactive isotope Strontium-90 is a high-energy beta emitter and can be used for generating electricity in remote weather stations, navigation buoys, and space vehicles ^{[1, 3]}.
• Strontium-90 can as well be used for removing static charges from machinery that handles plastic or paper ^[1].
• Strontium chloride along with strontium acetate, used as an ingredient in toothpaste, helps in relieving pain caused by sensitive teeth ^[11].
• Research indicates that intravenous Strontium-89 chloride can be used for reducing pain associated with metastatic bone cancer ^[11].

Toxicity of Strontium

Some deep-sea creatures incorporate strontium into their shells, and thus the element is necessary for some stony corals ^[1]. Like calcium, it can be absorbed by human bones, but is not harmful and does not play any biological role in our body ^[1]. Exposure to radioactive ⁹⁰Sr, an extremely hazardous component in the fallout from nuclear power plant accidents and nuclear explosions, can increase the risks of developing cancers of blood, nose, lung, and the bone ^{[1, 3, 12]}.

Interesting Facts

• Strontium is a common element in nature and is 15th most abundant in Earth’s crust ^[3].
• When it reacts with water, it produces strontium hydroxide, which is a severe respiratory, skin and eye irritant ^[3].
• The element is graphically represented by an abstract image of a metallic mushroom cloud, indicating its presence in nuclear fallout ^[1].

Cost of Strontium

The price of pure strontium is about $1 per gram ^[6].

References
1. http://www.rsc.org/periodic-table/element/38/strontium
2. https://education.jlab.org/itselemental/ele038.html
3. https://www.livescience.com/34522-strontium.html
4. https://wwwrcamnl.wr.usgs.gov/isoig/period/sr_iig.html
5. https://education.jlab.org/itselemental/iso038.html
6. https://www.chemicool.com/elements/strontium.html
7. https://www.webqc.org/molecular-weight-of-Strontium.html
8. http://periodictable.com/Elements/038/data.html
9. https://pubchem.ncbi.nlm.nih.gov/compound/strontium_ion#section=Top
10. http://chemistry-reference.com/q_elements.asp?Symbol=Sr&language=en
11. https://www.webmd.com/vitamins/ai/ingredientmono-1077/strontium
12. http://www.dhss.delaware.gov/dph/files/strontiumfaq.pdf